This material is based upon work supported by the National Science
Foundation under NSF-REU Grant No. PHY/DMR-1004811, NSF-RUI Grant No.
DMR-1104725, and NSF-MRI Grant No. CHE-0959282.

A nanoporous thin film’s high surface area allows it to act as a particularly
efficient capacitor and gives it enhanced catalytic properties. This project
focuses on the electrodeposition and dealloying of nickel-cobalt thin films
with the purpose of creating such a nanoporous structure on the surface of
the film. Using an electrochemical cell and a three-electrode system nickel-cobalt
films of various ratios were deposited onto gold substrates. A scanning electron
microscope (SEM) with an energy dispersive x-ray spectroscopy (EDS) attachment
was used to observe and characterize each sample’s appearances, structures,
and compositions. The depositions were remarkably uniform and smooth. The only
defining characteristic was a large number of tiny holes measuring fractions
of a micron scattered across the surface in varying concentrations. Analysis
of the data gathered from the EDS showed that the percentage of cobalt in the
film averaged nearly double that in the solution, suggesting that, when the
two are deposited together, cobalt deposits at a much higher rate than nickel.
Select samples were then dealloyed in the same electrochemical cell. This was
achieved by reversing the potential across the electrodes, and, since cobalt
re-oxidizes at a lower potential, it should strip off first, leaving behind
an especially nanoporous surface. Preliminary results from the EDS suggest
that dealloying cobalt from a nickel-cobalt sample is more likely with a higher
cobalt to nickel ratio on the film.